From my email server:
2019-03-12 21:00:35 dovecot_login authenticator failed for srv.mynodehostname.com (localhost) [XXX.XXX.XXX.XXX]:38722: 535 Incorrect authentication data (set_id=admin@mymail.com)
I have double checked, host/user/pass are all correct.
My SolusVM can connect to my mail server using same details, checked user/pass through webmail and desktop email client, all working fine except Virtualizor.
Password is 12 character long, alpha numeric and with special characters.